Problem with Oracle 11.2.0.1

Following works on oracle 10g not on oracle11g.

SELECT column1,
 column2
FROM
 (SELECT 1 column1,2 column2,3 column3 FROM dual
 )
GROUP BY column1;

I found the same issue on Oracle Technology Forum (OTN). It seems there is a bug in Oracle 11.2.0.1.

this would be fixed by suggested workaround in the oracle forum.

Following should be set by Database administrator.
    set "_optimizer_group_by_placement"=FALSE

Reference: http://forums.oracle.com/forums/thread.jspa?threadID=1128695